Reverse circulation rotary rock bit



May 19, 1959 CB. DAY

' REVERSE CIRCULATION RQTARY ROCK BIT 2' Sheets-Sheet ,1

Filed Feb. 8, 1956 FIG. 7

IN V EN TOR.

ATTORNEY M y 1959 c. B. DIAY I 2,887,301

REVERSE CIRCULATION ROTARY ROCK BI'I Filed Feb. 8, 1956 2 Sheets-Sheet 2 VENTOR.

ATTORNEY its axis. and downwardly in diverging relation from the periphery I I of the body 20, and all terminate in a common horiz ontal plane extending radially from the body 20 and above the lower end 26 of the body. In the preferred embodiment, the members 24 are substantially rectangumoved and replaced, thereby adding considerably to the per se;

Figure 4 is a fragmentary elevational view of one of the rotating-cone pilot cutter support arms;

Figure 5 is a vertical cross sectional view taken substantially. along line 5--5 of Fig. 4;

Figure 6 is afvertical cross sectional view taken substantially along line 66' of Fig. 3; and

Figure 7 is a fragmentary top view of one of the support member s connected to the tubular body, the body being shown in cross section.

Like characters of reference designate like parts in those figures of the drawings in which they occur.

In the drawings:

Referring more particularly to Fig. 1, the reference .numeral 10 indicates, as a whole, the device which is connected to the lower end of a rotary drill string 12.

Water, or drilling fluid 14 from a pit, not shown, adjacent the surface of the earth enters the annulus of the drilled bore 16 around the drill pipe and flows downwardly by gravity in the direction of the arrows through the bottom of the device 10 in a manner more fully de' shown. .,The above description is conventional with revierse circulation methods of drilling and is given here scribed hereinbelow, and upwardly through the bore of i the drill pipe 12, from which it is removed through the kelly or drive joint and the swivel, by a suction pump, not

only; to set forth the fundamentals of this method of 1 drilling for which the present invention isprimarily designed.

1 Referring now to Fig. 3, it may be seen that the device-.10 comprises a vertically disposed tubular body 20, open at both ends, providing a fluid course 21 therethrough and having a flanged upper end 22 for connection with the drill pipe 12. The drill pipe illustrated has a relatively thin wall and features flanged connections 13. rather than screw-threaded tool joints to add rigidity to the drill string. Diamertically the body 20" is substantially equal to the drill pipe 12, and the bore 21 of the body is in alignment with the bore of the drill pipe. It is to be understood, of course, that conventional threads and couplings may be used for connecting the drill pipe to the drill 10 if desired.

A plurality of support members 24 are rigidly connected to the periphery of the body 20, intermediate its ends, in equidistantly radially spaced-apart relation about The members 24 extend angularly outwardly nected tothe periphery of the body 20 adjacent its lower end 26. The periphery of the flange 28 is provided with a like plurality, with relation to the members 24, of

straight edge portions 29 in co-operating parallel relation with the lower end portion of the inwardly disposed flat surface of each respective member 24. The length of the straight edge portion 29 is preferably substantially equal with relation to the diameter of the spindle of a cutter to be attached thereto, as is more fully explained 'hereinbelow. A truncated conical cutter 30 is rotatably journaled and extends substantially the entire distance between the lower extremity of each member 24 and the straight portion 29 of the flange 28. Each cutter 30 comprises a spindle 32, bearings 34 carried in races at opposing ends of the spindle, and a truncated conical toothed shell 37 adapted to revolve on the bearings. The assembled spindle 32 and bearing race 33- is rigidly welded in place at each end, as at 36, between the adjacent flat inner surface of the member 24 and the co-operating straight edge portion 29 on the flange 28, with the longitudinal axis of the spindle lying within a conical vsurface generated about the longitudinal axis of the body. The teeth 38 of the cutters 30 are arranged in radially equidistantly spaced-apart wedge shaped rows disposed longitudinally of the cutter. The ends of each respective row of teeth 38 are cut off, as at 39, toprovide clearance between the same and the adjacent parts of the drill. The outwardly disposed end of each row of teeth 38 projects slightly beyond the radially outward limit of the respective member 24 for cutting a bore slightly larger diametrically than the drill, in order that the same may rotate freely within the walls thereof.'

7 A multiple cone pilot cutter, preferably a triple cone cutter 40, is rigidly connected, as by welding the 'cutter head or frame 42, to the lower surface of the flange 28. The triple cone cutter 40 is substantially'conventional with such cutters, except for the head 42 which has a central bore for co-operative communication with the bore 21 of the body 20 to provide a fluid course therethrough. The cutter head 42 has three equidistantly radially spaced depending arms 44, to each of which is rigidly connected a cone spindle 46 which journals a toothed cutting cone 48 by bearings 50. The spacing of the cones 48 is such that the cutting surfaces on-the same lie in spaced-apart relation 'so that lumps of drilled formation may be carried upwardly therebetweenbythe 'flowing action of the drilling fluid 14. As illustrated more clearly in Figs. 4 and 5, a lip or fillet 52 is formed of each side of the arm 44 to form a recess, as at 54, :at the angular juncture of the arm 44 with the cutter head 42. The recess 54 is necessary to provide clearance of the teeth at the base of the cone cutter 48, and the filleted corner 52 acts to direct the drilling fluid 14 downwardly to flow across the teeth of the cone cutters 48 to clean the same and remove the formation cuttings, not shown. At least one of the cone cutters has a tip 56 extending at least to the vertical axis of the body 20 to break the core formed by the two other cones 48. The cutter 40 cuts a substantially flat bottomed hole. Diametrically the ratio between the pilot cutter 40 and the annular ring formed around the same by the truncated cutters 30, maybe varied in proportion with the diameter of the -of the teeth of each cone cutter 48, and the inwardly projected limit of the teeth 38 of the single cutters 30, overlap slightly to completely drill all the encountered formation. Similarly it is desirable that the cutter 40 depend from the lower end of the body 20 a. suflicient distance so that a line 70 drawn between theoutwardly projected limit of the teeth on the cone cutter 48, and the outwardly projected limit of the teeth of the cutters inside 1' In order to insure a washing action across the teeth 38 of the truncated cutters 30 by the drilling fluid 14, the space formed betweeneach support member 24and the 'wall of the body 20 is substantially filled by a web 60 rigidly connected to the respective arm and the wall of the, body 20. The 'web60 is helically joined to the walllof the bbdyQas more clearly illustrated in Fig. 7,

wherein. the dotted lines 62jindicate the top of the web, and the dotted lines 64 indicate the bottom or depending Iedgeof the same lying in relativelyblose spaced paral- "l'ljrelation with the upwardly disposed surface of the teeth 38 of the revolving cutters 30. The helix of the web connection to the body winds upwardly toward the left, as seen 'in Fig. 1, so that,fas the drill is rotated clockwise,"asshownbythe'arrow' 72 (Fig. 7), the drilling fluid is urged downwardly, as indicated by the arrow 73 (Fig. 3) by the "surface of the web agairjstthe teeth 38, and against the directionof rotation of the cutters,

the depending ed'ge64. Thus, as the drill is rotated and"the cutters revolve, the webs60 create a washing action directed toward. the teethof the respective cutters to reinovejthe formation cutting therefrom and circulate lthe same downwardly to the lovver end 26 of the body '20, as"s"hown bythe direction arrows'in Fig. 3, and thence upwardlyto the surface of the earth.

I Referring to Fig. 2, it may be seen that the periphery of the flange 28 is arcuately formed inwardly between each pair of straight edge portions 29, as at 66, which allows for more freedom offiow of the drilling fluid downwardly between the adjacent cutters 30, and directs the fluid towardthe multiple cone pilot cutter head42. u u u u v u The respective cutters 48and 30 are removed for repair or replacement by the use of a cutting torch which is conventional with rotary rock bits.

Obviously the invention is susceptible to some change or alteration without defeating its practicability, and I therefore do not wish to be confined to the preferred embodiment shownin the drawings and described herein, further than I am limited by the scope of the appended claims.

I claim: 1. A counterboring rotary. drill, comprisingz a vertical- *ly disposed tubular body having the upper end thereof adapted-to. be connected to the lower end of a drill string and rotated therewith; a plurality of support members each rigidly connected at one end to the periphery of said body in equidistant radially spaced relation about its axis and extending angularly outward and downward therefrom intermediate the ends of said body and terminating in a common horizontal plane at their lower ends adjacent the lower end of said body in outward equidistantly spaced relation therefrom; a like plurality of spindles extending between and connected with the lower extremity of each said support member and the lower end of said body; a like plurality of truncated conical cutters journaled by said spindles, the axis of the respective truncated cutters lying within a conical surface generated about the longitudinal axis of said body; and a triple cone cutter having a frame, said frame rigidly mounted on the lower extremity of said body, said triple cone cutter frame having an opening therethrough in communication with the bore of said body, the radially outward projected limit of each said truncated cone cutter extending only a short distance outwardly of the radially outward extending limit of the support member which carries the particular truncated cone cutter to provide circulation clearance between said members and the bore wall.

2. Structure as specified in claim 1, in which the length of each truncated conical cutter is such that the same will make an annularcut slightly overlapping inwaidl y aiht "inade by said triple cone pilot cutter.

3. Structureas specified in claim :1,"in plane contacting the outwardly projected lower limit ofeachirespective truncated conical cutter, and eachti iplejcone pilot cutter, is disposed substantially at an angle of 30 degrees with relation to a'horizontal plane extending fasupport members each rigidly connected at. oneend tof the periphery of said body in equidistant radially' spaced'relation about its axis and angularly extending outward and downward therefrom intermediate the endsof'saidbody, said support members terminating in a'common'horizontal plane at their lower ends in outward equi-dis tantradially spaced relation from the lower end of said body;' a centrally bored, plate rigidly connected to theperipheryfof said body adjacent its lower end; a like plurality of spindles extending between and connected with the lower extremity of each said support member and the "periphery of said plate, a like plurality of truncated conical cutters journaled by said spindles; the axis of the respe'ctiveftruncated cutters lying within a conicalsuiface generated about the longitudinal axis of said body; a'pilot cutter head rigidly mounted on the lower end of said'body, said pilot cutter head having three downwardly and inwardly projecting radially spaced-apart spindles; conical cutters rotatably carried by said cutter head spindles,the apex of at least one conical cutter extending to the vertical axis of. said body; and means for directing fiuidwithinfthe drilled bore againstthe teeth of said truncatedconi cal cutters and said conical cutters in a washing'action for cleaning the same. u 7 I 5. Structure as specified in claim4, in whichthemeans includes a helically disposedweb joining the -upper end portion of each said support member with the adjacent portion of said b ody,the depending edge of each saidweb lying in relatively close spaced relationwith the upwardly withinthe drilled hole is directeddownwardly aerhss the teeth of that particular cone cutter as the drill is rotated.

7. Structure as specified in claim 4, in which the length of each truncated conical cutter is such that the same will make an annular cut slightly overlapping inwardly the cut made by said cones of said pilot cutter.

8. Structure as specified in claim 4, in which a plane contacting the outwardly projected lower limit of each respective truncated conical cutter, and the adjacent cone of the pilot cutter, is disposed substantially at an angle of 30 degrees with relation to a horizontal plane extending radially with relation to the axis of said body.

9. A reverse circulation rotary drill, including: an open-ended vertically disposed tubular body and having a horizontally disposed flange adjacent its lower end, said body having a flanged upper end adapted to be connected to the lower end of a drill string and rotated therewith; a spindle equipped multiple cone pilot cutter frame rigidly connected to the lower surface of said horizontal flange, said cutter frame having a fluid course therethrough in communication with the bore of said body; a pilot cutter cone journaled by each spindle on said cutter frame; a plurality of support members each rigidly connected at one end to the periphery of said body in equidistant radially spaced relation about its axis and angularly extending outward and downward therefrom intermediate the ends of said body, said support members terminating in 'a common horizontal plane at their lower ends in out- Ward equidistant radially spaced relation from said'horij' zontal flange; a like plurality of truncated conical cutters each having a spindle extending between and connected with the lower extremity of each said support member andthe periphery of said flange for journaling said truncated cutters, the axis of the respective truncated cutters lying within a conical surface generated about the longitu'dinal axis of said body, the truncated end of said truncated cutters disposed downwardly against said horizontal flange, said horizontal flange having inwardly directed arcuate recesses between its connections with said truncated cutter spindles for permitting the free passage of fluid downwardly toward the lower end of said body; and

means for directing fluid within the drilled bore against the teeth of said truncated cutters in a washing action for cleaning same.

10. Structure as specified in claim 9, in which the means includes a helically disposed web joining the upper end portion of each said support member with the adjacent portion of said body, the depending edge of each said web lying in relatively close spaced relation with the upwardly projecting teeth of each particular truncated conical cutter, whereby rotation of said drill causes said webs to direct fluid Within the drilled bore downwardly against said rotating truncated conical cutters.

11. Structure as specified in claim 9, in which the length of each truncated conical cutter is such that the same will make an annular cut slightly overlapping inwardly the cut made by said multiple cone pilot cutter.

12. Structure as specified in claim 9, in which a plane contacting the outwardly projected lower limit of each respective truncated conical cutter, and the adjacent cutter of said multiple cone pilot cutter, is disposed sub- :stantially at an angle of 30 degrees with relation to a horizontal plane extending radially with relation to the Y axis of said body.

13. A reverse circulation rotary drill, including: an

open-ended vertically disposed tubular body having a horizontally disposed flange adjacent its lower end, said body having a flanged upper end adapted to be connected to connected to the lower surface of said horizontal flange,

said cutter frame having a fluid course therethrough in communication with the bore of said body; a pilot cone cutter journaled by each spindle on said cutter frame; a plurality of support members each rigidly connected at one end to the periphery of said body in equidistant radially spaced relation about its axis and extending angulanly outward and downward therefrom intermediate the ends of said body, said support members terminating in a common horizontal plane at their lower ends in outward equidistant radially spaced relation from'said flange; a like plurality of spindles extending between and rigidly connected with lower end portion of each respective said support member and the adjacent peripheral portion of said horizontal flange, the axis of the respective spindles lying within a conical surface generated about the longitudinal axis of said body; a like plurality of truncated conical cutters journaled by said spindles and extending between each respective said support member and the adjacent edge of said horizontal flange; longitudinally extending wedge shaped teeth having cutting edges on each said truncated cutter; and means for directing fluid within the drilled bore against the teeth of each said truncated cutter in a washing action for cleaning the same.

14. Structure as specified in claim 13, in which the means includes a helically disposed web joining the upper end portion of each said support member with the adjacent portion of said body, the depending edge of each said web lying in relatively close spaced relation with the upwardly projecting teeth of each particular truncated conical cutter, whereby rotation of said drill causes said webs to direct fluid within the drilled bore downwardly against said rotating truncated conical cutters.

15. Structure as specified in claim 13, in which the length of each truncated conical cutter is such that the same will make an annular cut slightly overlapping inwardly the cut made by said multiple cone pilot cutter.

16. Structure as specified in claim 13, in which a plane contacting the outwardly projected lower limit of each respective truncated conical cutter, and the adjacent cutter of said multiple cone pilot cutter, is disposed substantially at an angle of 30 degrees with relation to a horizontal plane extending radially with relation to the axis of said body.

References Cited in the file of this patent UNITED STATES PATENTS 1,868,348 De Costa July 19,1932 2,058,628 Reed Oct. 27, 1936 2,147,927 Scott Feb. 21, 1939 2,208,530 Thompson July 16, 1940 2,557,619 Swart June 19, 1951 2,703,698 Westerman Mar. 8, 1955 

